CN1196970C - Display device - Google Patents

Abstract

A video display apparatus is disclosed which exhibits high utilization efficiency of a luminous flux from a light source and can provide a uniform video. The video display apparatus includes a light source unit including a plurality of coupling optical elements for converting light emitted from a plurality of light sources into a substantially parallel luminous flux and operable to condense light having passed through the coupling optical elements at a predetermined position, an optical integrator for uniformizing the intensity distribution of the condensed light, and a light valve.

Description

display device

technical field

This invention relates to video display devices for projecting a still or moving picture with high color reproduction.

Background technique

A projection type video display device is generally used in practice, which projects and displays a still or moving picture on a screen using light emitted from a certain light source.

A conventionally widely used projection type video display device generally has such a configuration as shown in FIG. 1 . Referring to Fig. 1, the projection-type video display device comprises a reflector 100 having a rotating parabolic reflective surface, a light source 101 positioned at the focal point of the reflector 100, an integrator 102, a red beamsplitter 103R, a green beamsplitter 103G, a reflector Mirror 103B, and a cubic color synthesis prism 104.

The video display further includes a reflection mirror 105R for reflecting red light rays reflected by the red dichroic mirror so as to be introduced into a predetermined plane 104R of the color synthesis prism 104, and a reflection mirror 105B for reflecting blue light rays reflected by the reflection mirror 103B , so as to be introduced into another plane 104B of the color synthesis prism 104 parallel to the plane 104R. The color synthesizing prism 104 is arranged such that the green light reflected by the green dichroic mirror 103G is introduced onto a plane 104G perpendicular to the plane 104R and the plane 104B. A pair of optical path length adjustment lenses 106 and 107 are placed between the green dichroic mirror 103G and the reflection mirror 103B, and between the reflection mirror 103B and the reflection mirror 105B, respectively.

The video display device further includes a red light valve 108R placed between the mirror 105R and the plane 104R of the color synthesis prism 104, a red lens 109R placed between the mirror 105R and the red light valve 108R, and a green dichroic mirror 103G and the green light valve 108G between the plane 104G of the color synthesis prism 104, the green lens 109G placed between the green dichroic mirror 103G and the green light valve 108G, the green lens 109G placed between the reflection mirror 105B and the plane 104B of the color synthesis prism 104 The blue light valve 108B, and the blue lens 109B placed between the mirror 105B and the blue light valve 108B.

The video display device further includes a projector lens 110 located opposite the other plane of the color synthesis prism 104 parallel to the plane 104G.

In a conventional video display having the above configuration, a white light lamp such as a xenon lamp or a metal halide lamp is used as the light source 101 . Light emitted from the light source 101 is reflected by the reflection plate 100, and then, after ultraviolet rays and infrared rays are removed from the light by a cut filter (not shown in the figure), is introduced into the red beam splitter 103R by the integrator 102. Of the rays introduced into the red dichroic mirror 103R, components of the red light are reflected by the red dichroic mirror 103R and the reflection mirror 105R, and then pass through the lens 109R and the red light valve 108R, thus being introduced into the color synthesis prism 104. Whereas, among the light rays introduced into the red dichroic mirror 103R, light components of other colors than the red light rays pass through the red dichroic mirror 103R, and are introduced into the green dichroic mirror 103G.

Of the light introduced into the green dichroic mirror 103G, a green ray component is reflected by the green dichroic mirror 103G, and is introduced into the color synthesis prism 104 through the green lens 109G and the green light valve 108C. Whereas, among the light rays introduced into the green dichroic mirror 103G, light components of other colors than the green light beam pass through the green dichroic mirror 103G, and are introduced into the reflection mirror 103B through the optical path length adjustment lens 106 .

The light introduced into the reflection mirror 103B, that is, the blue light component, is reflected by the reflection mirror 103B and passes through the optical path length adjustment lens 107, and thereafter, is further reflected by the reflection mirror 105B, and then passes through the blue lens 109B and the blue light valve 108B is introduced into the color synthesis prism 104.

The colored light components introduced into the color synthesizing prism 104 are synthesized by the color synthesizing prism 104 and projected on a transmissive or reflective screen through a projector lens 110 .

In a conventional video display, since a single kind of light source is used alone as the light source 101 by itself, the wavelengths included in the light emitted from the light source 101 are somewhat shifted to one side, therefore, to obtain It is difficult to balance the light quantity ratio of the three colored light components separated by the mirror 103B. Therefore, it is difficult to increase the color reproducibility of conventional video displays. Furthermore, since white light lamps used in conventional video displays have difficulty in high-precision brightness adjustment and emit light at a certain fixed brightness, adjusting the brightness independently for each of the red, green, and blue light components is a difficult.

Further, in a conventional video display, a light beam emitted from a white light lamp used as the light source 101 has a ring-shaped cross section. In contrast, the light valves 108R, 108G, and 108B, which are normally illuminated by light, are rectangular. Therefore, in order to uniformly introduce light into the light valves 108R, 1086, and 108B, the diameter of the light beam incident to each light valve is set to be larger than the length of the diagonal of each light valve. Thus, there is a problem that the irradiation efficiency of the light irradiated from the light source 101 is very low.

Therefore, it has been proposed to use another video display device that uses a plurality of lamps as its light source, or uses a plurality of semiconductor light emitting elements such as light emitting diodes or laser diodes for each of the three basic colors.

Figure 2 shows an XY chromaticity diagram illustrating the range of color reproduction of phosphors in CRTs (cathode ray tubes), video display devices using light-emitting diodes, and display devices of the NTSC (National Television Systems Committee) system; from the XY chromaticity It can be seen from the figure that the light-emitting diode is used as a light source, and its color reproduction range is larger than that of the phosphor of a CRT or the display device of an NTSC system.

However, due to the angle of the rays emitted from multiple light sources, off-axis light from outside the optical axis is generated. If off-axis light is included in the light emitted from the light source, it is difficult to uniformly irradiate the light on the light valve. Furthermore, since the light is irradiated to the outside of the light valve, the light irradiation efficiency is disadvantageously impaired.

Contents of the invention

An object of the present invention is to provide a video display device in which a plurality of white light lamps having excellent color purity, or a plurality of semiconductor light emitting elements are used as a light source, and light emitted from the light source can be uniformly and efficiently introduced into the a light valve.

In order to achieve the object of the present invention, a video display device is provided, comprising: a light source part including a plurality of light source parts, each light source part includes a light source formed by a semiconductor light emitting element or a white light lamp, and a light source for emitting light from the light source A coupling optical element that converts the light into substantially parallel light, and the light source part includes a condenser lens capable of concentrating light from the light source part and having passed through the coupling optical element in the video condensing light at a predetermined focus position of an optical axis of a light illumination system of a display device, wherein the light source part is arranged on a plane of the light source part so that light from the light source part is condensed on the condensing lens the predetermined focal position of the light source; an integrator disposed on the focal position of the light source part for uniformizing the in-plane optical density distribution of the light emitted from the light source part; and a rectangular light valve whose plane The light whose inner light intensity distribution has been homogenized by the integrator is irradiated thereon; wherein, the focal distance of the condenser lens is represented by L, and, from the optical axis of the light illumination system of the video display device The maximum distance to the optical axis of each of the light source parts is denoted by H, and the light source parts are designed so as to satisfy the relationship given by the following formula: |H/L|<0.27.

The present invention also provides a video display device, comprising: a light source part including a plurality of light source parts, each light source part including a light source formed by a semiconductor light emitting element or a white light lamp, and for converting light emitted from the light source into a parallel light coupling optical element, the light source is capable of focusing the light from the light source part and having passed through the coupling optical element at a predetermined focus position on the optical axis of the light illumination system of the video display device, Wherein, the light source part is arranged on a hemisphere with the focus position as the center, so that the light from the light source part can be focused on the focus position; the integral placed on the focus position of the light source part a light valve for uniformizing the in-plane optical density distribution of the light emitted from the light source part; and a rectangular light valve on which the light whose in-plane light intensity distribution has been uniformized by the integrator is irradiated ; Wherein, the focal distance is represented by L, and the maximum distance from the optical axis of the light illumination system of the video display device to the optical axis of each of the light source parts is represented by H, and the light source components are represented by This is designed so that the relation given by the following formula is satisfied: |H/L|<0.27.

With the above-mentioned video display device, since the light emitted from the plurality of light source sections is concentrated and introduced into the light valve, the number of light source sections can be increased to easily increase the amount of light, if necessary. Further, since the light from the plurality of light source parts is concentrated at a predetermined focal position on the optical axis of the entire illumination system, and the integrator is placed at the focal position, the light can be uniformly irradiated on the light valve, Also, light emitted from the light source portion can be efficiently introduced into the light valve.

The balanced light quantity ratio of the three primary colors can be obtained, and the brightness can be adjusted with high precision by using a plurality of different types of white light lamps or a plurality of semiconductor light-emitting elements with good color impurity. Accordingly, such a video display device can be formed so as to exhibit its high brightness, high color reproducibility, and high performance.

Description of drawings

The above and other objects, features and advantages of the present invention will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings, in which like image parts or elements are denoted by like reference symbols.

Fig. 1 is a schematic diagram showing a conventional video display device of a projection type;

Figure 2 illustrates the color reproduction range of different conventional video display devices;

Fig. 3 has provided an example of the configuration of the video display device to which the present invention is applied;

Fig. 4 is a schematic diagram showing an example of the configuration of the illumination optical system placed in the video display device of Fig. 3;

Figure 5 shows an example of the configuration of light emitting diodes placed in the video display device of Figure 3;

Figure 6 illustrates a geometrical relationship of the optical system of the video display device of Figure 3;

Figure 7 illustrates the lighting conditions of the video display device of Figure 3 on the light valve;

Fig. 8 illustrates the relationship between θ _LED1 /NA _EYE1 and the irradiation efficiency of light on the light valve in the video display of Fig. 2;

9A and 9B illustrate the focal positions of the condenser lenses placed in the light source part of the video display device of FIG. 3 when light is input to the optical axis in parallel and obliquely, respectively, while FIG. 9C illustrates a plurality of light source parts and condenser lenses positional relationship between

Figure 10 illustrates the positional relationship between the light source part and the integrator, where the video display device of Figure 3 includes a condenser lens;

Fig. 11 shows the video display device of Fig. 3, here, a plurality of light source parts are placed on a hemisphere, and needn't dispose condensing lens;

Figure 12 illustrates a positional relationship between the light source part and the integrator, where the video display device of Figure 3 does not include a condenser lens;

FIG. 13 shows an example of the configuration of another video display device to which the present invention is applied;

Fig. 14 shows an example of the configuration of the polarization conversion element which can be provided in the video display device according to the present invention.

Detailed ways

Referring to FIG. 3, this figure shows a video display device applying the present invention. The shown video display device is generally denoted 1 and includes a cubic dichroic prism 2, a green illumination optical system 3G placed opposite a plane 2G of the dichroic prism 2, a dichroic prism placed perpendicular to the plane 2G The red illumination optical system 3R is placed opposite the plane 2R of the dichroic prism 2, and the blue illumination optical system 3B is placed opposite the plane 2B of the dichroic prism 2 parallel to the plane 2R.

The video display device 1 further comprises a projector lens 4 placed opposite the remaining plane of the dichroic prism 2 parallel to the plane 2G. When the light synthesized by the dichroic prism 2 from the light emitted from the illumination optical systems 3G, 3R, and 3B is input, the projector lens 4 has a function of projection as a screen (not shown) such as in a light transmission type or a reflection type. A video such as a still or moving picture on ). It should be noted that the projector lens 4 may have a structure similar to widely conventionally used video display devices, and therefore, a detailed description of the projector lens 4 is omitted in the following description.

The video display device 1 has such a configuration as described above. In video display device 1 , red light, green light, and blue light are respectively emitted from red illumination optical system 3R, green illumination optical system 3G, and blue illumination optical system 3B, and are introduced into dichroic prism 2 independently of each other. Rays of light of three colors are synthesized by a dichroic prism 2 and then introduced into a projector lens 4 . In the video display device 1, since rays of light of different colors are emitted from the illumination optical system independently of each other in this manner, the reproducibility or brightness of each color can be adjusted with high precision.

The above-described red illumination optical system 3R, green illumination optical system 3G, and blue illumination optical system 3B will be described in more detail below. It should be noted that since the red illumination optical system 3R, the green illumination optical system 3G, and the blue illumination optical system 3B may have substantially similar configurations, the illumination optical system 3 described below represents the red illumination optical system 3R, the green illumination optical system 3G and blue illumination optical system 3B.

Referring to Fig. 4, the illumination optical system 3 includes a light source part 11 having a plurality of light source parts 10, which can condense the light from the light source part 10 at a predetermined position on the optical axis of the whole lighting system, including placing the light source part 11 Integrator 12, first condenser lens 13, second condenser lens 14 and light valve 15 at the focal point. The illumination optical system 3 is arranged such that the light valve 15 therein can face the dichroic prism 2 of the video display device 1 .

Each light source section 10 includes a light emitting diode 16 as a light source, and a coupling lens 17 for changing light emitted from the light emitting diode 16 into substantially parallel light. In the light source section 11, each light source section 10 formed of a light emitting diode 16 and a coupling lens 17 are placed on one plane. The light source part 11 further includes a condensing lens 18 for condensing the light from the light source part 10 at a predetermined position on the optical axis of the entire illumination optical system.

The integrator 12 is placed at the focus position of the condenser lens 18 of the light source part 11 , and has a function of uniformizing the in-plane optical intensity distribution of the light emitted from the light source part 11 . The integrator 12 is composed of a first fly's eye lens 19 and a second fly's eye lens 20 . The first fly's eye lens 19 and the second fly's eye lens 20 are arranged as conjugate and form a telecentric optical system.

The first condenser lens 13 and the second condenser lens 14 have a function of condensing and introducing the light that has passed through the integrator 12 into the light valve 15 .

In the illumination optical system 3 , the light emitted from the light emitting diode 16 is changed into substantially parallel light by the coupling lens 17 . Since the light-emitting diodes 16 form a planar illumination, there is off-axis light from outside the optical axis. The light that has passed through coupling lens 17 is refracted by condenser lens 18 and introduced into integrator 12 . Integrator 12 aligns the angular distribution of off-axis light with respect to the optical axis in order to homogenize the in-plane optical intensity distribution. The light that has passed through the integrator 12 is introduced into the first condenser lens 13 .

In the illumination optical system 3, the first condenser lens 13 and the second condenser lens 14 are placed at conjugate positions, thus forming a telecentric optical system as described above. Then, the light that has passed through the first condenser lens 13 and the second condenser lens 14 and is converted is introduced into the light valve 15 again.

The illumination optical system 3 is configured as described above, and the red illumination optical system 3R, green illumination optical system 3G, and blue illumination optical system 3B basically have a configuration similar to that of the illumination optical system 3 . However, the red illumination optical system 3R, the green illumination optical system 3G, and the blue illumination optical system 3B are configured such that red, green, and blue light beams are thereby introduced into the dichroic prism 2, respectively. More specifically, for example, the light emitting diode 16 as a light source may emit red, green, and blue lights. Also, for example, the illumination optical system 3 may include various color filters, so that the light emitted from the light emitting diode 16 can be wavelength-converted into red, green, and blue lights by using the color filters.

Each of the red illumination optical system 3R, the green illumination optical system 3G, and the blue illumination optical system 3B in the video display device 1 includes a light valve 15 . The red, green, or blue light beams irradiated on the light valve 15 in each illumination optical system 3 are spatially adjusted by the light valve 15 and then input to the dichroic prism 2 . The red, green and blue light beams inputted into the dichroic prism 2 are synthesized by the dichroic prism 2 and projected on the screen through the projector lens 4 .

With video display device 1 having the above configuration, since light emitted from light source portion 10 is condensed and input to light valve 15, the number of light source portions 10 can be increased so that the amount of light can be easily increased if necessary. Furthermore, since the light from the light source portion 10 is condensed at a predetermined focal position on the optical axis of the entire lighting system, and the integrator 12 is placed on the focal position, the light can be uniformly irradiated on the light On the light valve 15, and the light energy from the light source portion 10 is effectively input to the light valve 15.

It should be noted that, for the light source of the light source section 10 in the above-mentioned video display device 1, various semiconductor light emitting elements such as laser diodes, or white light lamps such as discharge lamps such as metal halide lamps or hydrogen halide lamps, Can be used instead of LED 16. Where white light is used as the light source, various color filters can be used to convert the white light wavelength-converted into red, green and blue beams, which are irradiated on the dichroic prism 2 .

When the light-emitting diode 16 is used to directly emit red, green and blue light beams without using various color filters, for the red semiconductor light-emitting element, GaP-type, GaAsP or AlGaPAs such as GaAlAs, GaAsP or AlGaPAs can be used. GaAs type or AlAs type mixed semiconductor. For a green semiconductor light-emitting element, a GaN-type or ZnSe-type mixed semiconductor such as InGaN or AlInGaN can be used. Furthermore, GaN-type, ZnSe-type, or SiC-type mixed semiconductors such as InGaN or AlInGaN can be used for blue semiconductor light-emitting elements.

Further, in the video display device 1 according to the present invention, the light emitting diode 16 as the light source of the light source part 10 may include a reflector (reflector) 21 for reflecting light so that it is emitted toward one direction, as shown in FIG. 5 shown. The use of the mirror 21 increases the utilization efficiency of the light emitted from the light emitting diode 16 and makes it possible to display bright video with low output power. It should be noted that effective light condensation properties can be obtained by configuring the light source with reflectors in this way, and the light source part 10 may not include the coupling lens 17 .

Furthermore, in the video display device 1 described above, various coupling optical elements having a function of condensing light emitted from a light source may be used instead of the coupling lens 17 . Further, although the video display device 1 uses condensing lenses to refract light, a similar result can be expected even if each condensing lens is replaced here with a Fresnel lens having diffractive activity.

The optimum geometrical relationship with respect to the positions of the light emitting diodes 16 and the individual lenses in the video display device 1 described above will be described below.

First, the geometric relationship between the light emitting diode 16 and the lenses suitable for uniformizing the light emitted from the light emitting diode 16 and achieving high illumination efficiency to the light valve 15 will be described with reference to FIG. 6 . Here, the minor side direction of the light valve 15 is described. The subscript “1” used in the following description indicates the minor lateral orientation of the light valve 15 , while the subscript “2” indicates the major lateral orientation of the light valve 15 .

Here, the length of the light-emitting diode 16 is represented by _r1 , the effective focal length of the coupling lens 17 is represented by _fLED , and the effective numerical aperture of the coupling lens 17 is represented by _NALED , and the optical coupling efficiency _ηLED of the light-emitting diode 16 is expressed by the following expression 1 means:

η _LED = NA _LED2 (Expression 1)

Equation 2 below expresses the maximum value θ _LED1 of the off-axis light angle with respect to the optical axis:

θ _LED1 = r ₁ /(2f _LED ) (Expression 2)

Equation 3 below gives the exit aperture diameter D _LED1 of the light that has passed through the coupling lens 17:

D _LED1 = 2NA _LED × f _LED (Expression 3)

From the expressions 2 and 3 given above, the following expression 4 can be obtained:

D _LED1 = NA _LED ×r ₁ /θ _LED1 (Expression 4)

Next, denote the number of element lenses of the first and second fly's eye lenses 19 and 20 by N1, denote the effective focal lengths of the first and second fly's eye lenses 19 and 20 by f _EYE , and denote the first and second by NA _EYE1 The effective numerical apertures of the fly-eye lenses 19 and 20 are represented by the following equation 5, the exit aperture diameter D _LED1 :

D _LED1 = 2N1 × f _EYE × NA _EYE1 (Expression 5)

Meanwhile, the effective focal lengths of the first and second condenser lenses 13 and 14 are denoted by _fc , and the maximum value of the angle of the light irradiated on the light valve 15 with respect to the optical axis is denoted by θ _LV1 , expressed by the following formula 6 Exit light hole diameter D _LED1 :

D _LED1 = 2f _c × θ _LV1 (Expression 6)

The length of the light valve 15 is denoted here by L L _LV1 , given by Equation 7 below:

2f _c ×NA _EYE1 = L _LV1 (Expression 7)

Here, from the equations 6 and 7 given above, the following equation 8 can be obtained:

NA _EYE1 = L _LV1 × θ _LV1 /D _LED1 (Expression 8)

Then, from the equations 4 and 8 given above, the following equation 9 can be obtained:

NA _EYE1 = θ _LED1 ×L _LV1 ×θ _LV1 /(NA _LED ×r ₁ ) (Expression 9)

Then, from the above formula 9, the following formula 10 can be obtained:

θ _LED1 /NA _EYE1 =r ₁ /L _LV1 ×NA _LED /θ _LV1 (Expression 10)

Here, the second fly's eye lens 20 is most meaningful when detecting the illumination conditions to the light valve 15 . As shown in FIG. 7 , light that has passed through one element lens 19 a of the first fly's eye lens 19 and then enters the corresponding element lens 20 a of the second fly's eye lens 20 is irradiated on the light valve 15 . However, light that has passed through the element lens 19 a of the first fly's eye lens 19 but entered an adjacent element lens 20 b of the second fly's eye lens 20 is not irradiated on the light valve 15 .

8 illustrates the relationship between the ratio between the inclination angle θ _LED1 of off-axis light and the effective numerical aperture NA _EYE1 of the first and second fly's eye lenses 19 and 20 and the irradiation efficiency on the light valve 15 .

Therefore, the illumination condition on the light valve 15 is given by the following expression 11:

θ _LED1 /NA _EyE1 ≤1 (Expression 11)

When θ _LED1 /NA _EyE1 ≤ 1, all the light emitted from the light emitting diode 16 is irradiated on the light valve 15, but when θ _LED1 /NA _EyE1 > 1, part of the light emitted from the light emitting diode 16 is irradiated on the light valve 15 outside, and this will reduce the light irradiation efficiency.

Here, the following expression 12 can be obtained from the expressions 10 and 11 given above:

r1≤L _LV1 ×θ _LV1 /NA _LED (Expression 12)

The expression 12 obtained in such a manner as described above subsumes itself to the Lagrangian-Helmholtz equation expressing the relationship between the measure of the object and the measure of the image.

It should be noted that although the above description refers to the minor side orientation of the light valve 15, the relationship given above applies equally to the major side orientation of the light valve 15. Therefore, in order to ensure high light irradiation efficiency on the light valve 15, the following expression 13 is also more suitable for the main side direction:

r2≤L _Lv2 ×θ _LV2 /NA _LED (Expression 13)

From the above description, in order to allow the light emitted from the light emitting diode 16 to be effectively irradiated on the light valve 15, the entire area S of the light emitting area of the light emitting diode 16 is preferably set to be smaller than (L _LV1 × θ _LV1 /NA _LED ) ×(L _LV2 ×θ _LV2 /NA _LED ).

Generally, when the light valve 15 is, for example, of a light-transmissive type, the maximum angles θ _LV1 and θ _LV2 of the illumination light to the light valve 15 with respect to the optical axis are limited by the contrast of the liquid crystal, the viewing angle of the projector lens, etc., similar to the second Factors related to the principal lateral orientation. Also, where the light valve 15 is reflective, the maximum angles θ _LV1 and θ _LV2 are limited by the contrast of the angle of incidence (depending on the polarizing prism), etc., similar to factors related to the minor and major side orientations. Therefore, in most cases, the maximum angles θ _LV1 and θ _LV2 are expressed by the relationship θ _LV1 = θ _LV2 . Furthermore, in general, the ratio of r1 and _r2 is equal to the ratio of L _LV1 and L _LV2 due to equal effective numerical apertures for directions equal to _the major and minor sides of the light valve 15 .

Therefore, the light emitting area formed by the plurality of light emitting diodes 16 of the light source part 11 preferably has a pattern like the light valve 15 . This enables the light from the light emitting diodes 16 to be introduced into the light valve 15 without loss, so that a high utilization efficiency of the light from the light emitting diodes 16 can be ensured.

It should be noted that in the video display device 1, not only the light emitting area of the light source part 11 but also the element lenses of the first and second fly's eye lenses 19 and 20 of the integrator 12 preferably have a pattern similar to that of the light valve 15. This can ensure that the light from the light-emitting diode 16 has a high utilization efficiency.

Here, the length L _LV1 of the secondary side direction and the length L _LV2 of the main side direction of the above-mentioned light valve 15 can be respectively the secondary side direction and the main side direction of the display part where the video is actually displayed (that is, the part that needs to be illuminated). length. In reality, however, since an aberration may cause non-uniform illumination, there is a possibility that a portion not illuminated by light may appear in the peripheral portion of the light valve 15 . Furthermore, from the manufacturer's standpoint, the irradiation area where the light is irradiated is preferably set to be slightly larger than the display portion in consideration of the margin of the area width.

Therefore, in the video display device 1, the length of the display portion in the secondary side direction is preferably less than the length L _LV1 of the light valve 15 in the secondary side direction, and the length of the display portion in the main side direction is smaller than that in the main side direction. The length L _LV2 of the light valve 15 .

Here, the irradiation area is set slightly larger than the display portion, video is not actually displayed on the peripheral portion where light is unlikely to be irradiated, and high irradiation efficiency can be obtained over the entire area of the display portion. More particularly, the length L _LV1 in the minor lateral direction and the length L _LV2 in the major lateral direction of the light valve 15 are preferably set to be greater than the minor lateral directions and The length of the display portion in the main side direction is about 5-10%. In addition, considering the margin for positioning, the length L _LV1 of the minor lateral direction and the length L _LV2 of the major lateral direction of the light valve 15 can be set equal to the device outer contour of the light valve 15, or set larger than the minor lateral direction. The length of the outer profile in the side direction and the main side direction is about 5-10%.

For example, the light emitting region of the LED 16 is substantially rectangular, the length of its minor side direction is r ₁ , and the length of its main side direction is r ₂ . In addition, the light emitting area of the light emitting diode 16 preferably has the same pattern as that of the light valve 15 . Here, the light emitting area of the light emitting diode 16 has the same pattern as that of the light valve 15, and the light is irradiated on the light valve 15 without loss, and high irradiation efficiency can be expected.

The geometric relationship between the light source portion 10 of the light source unit 11 and the condenser lens 18 will be described below.

If the angles of the rays entering the condensing lens 18 of the light source unit 11 are equal, their images are formed at substantially the same position. More specifically, if light rays parallel to the optical axis shown in FIG. 9A enter the condensing lens 18 (at an angle of 0 degrees), the incident ray is formed at the focal point on the optical axis and expands from the condensing lens 18 on the optical axis. elephant. Meanwhile, when light enters the condenser lens 18 at an angle of θ degrees with respect to the optical axis as shown in FIG. 9B, the incident light forms an image at a position perpendicular to the optical axis at a distance Y. The distance Y in this example is equal to the product of the distance L of the focal point and the angle of incidence θ.

Therefore, here, a large number of light-emitting diodes 16 are placed on the plane of the incident side of the condenser lens 18, as shown in Figure 9C, even if the light from the light-emitting diodes 16 is input on the different positions of the condenser lens 18, it is possible to A single beam is formed at the focal point. Therefore, in the video display device 1, a plurality of light-emitting diodes 16 and corresponding coupling lenses 17 are placed in the respective planes of the light source part 11, and the integrator 12 is placed at the focal position of the condenser lens 18, so that the above combined The description of Fig. 6 can be satisfied.

A case is discussed here: the focal length of the condenser lens 18 is denoted by L, and the distance from the optical axis of the entire lighting system to each light source part 10 is denoted by H, as shown in FIG. 10 .

As shown in FIG. 10, light from the light source section 10 at a position at a distance H from the optical axis is condensed by a condenser lens 18, and input to an integrator 12 at a certain predetermined angle. In this case, if the incident angle to the integrator 12 is relatively large, for example, light rays incident on the element lens 19a of the first fly-eye lens 19 cannot be introduced into the second fly-eye lens paired with the element lens 19a. 20 element lens 20a. Thus, the function of the integrator 12 is reduced and the amount of light irradiated on the light valve 15 is also reduced.

In the integrator 12, the confinement angle at which the light incident on the unit lens 19a of the first fly's eye lens 19 is introduced to the unit lens 20b next to the unit lens 20a of the second fly's eye lens 20 paired with the unit lens 19a is approximately 15 degrees. Therefore, the video display device 1 preferably satisfies the following expression 14:

|H/L|＜0.27 (expression 14)

In other words, the angle range value |H/L| of the light incident on the video display device 1 is preferably less than tan15°, ie less than 0.27. This eliminates an otherwise possible drop in the amount of light impinging on the light valve 15 and increases the utilization of light from the light reflecting diode 16 .

Incidentally, in the above description, the condensing lens 18 is provided in the light source section 11, and a plurality of light source sections 10 are placed on one plane. However, the present invention is not limited to this particular form. For example, the illumination optical system 3 can be constructed in another way, as shown in FIG. , the integrator 12 is placed at such a focal position that the light from the light source section 10 can be introduced into the integrator 12 .

In this case, the radius of the hemisphere on which the light source portion 10 is placed, that is, the distance from each light source portion 10 to the focus position is represented by L, and the distance from each light source portion 10 to the focus position is represented by H, As shown in Figure 12. Expression 14 given above is preferably satisfied as described above in connection with FIG. 10 .

Further, in the above description, the video display device 1 includes one light valve 15 in each of the illumination optical systems 3 of the red illumination optical system 3R, the green illumination optical system 3G, and the blue illumination optical system 3B. However, the present invention is not limited to this specific form. For example, the light synthesized in color by the dichroic prism 2 may be input to the light valve 15 in the form of a single plate.

In this case, the first condenser lens 13 comprises, as shown in FIG. 2G is a red light source part 11R opposite to the other surface 2R of the dichroic prism 2 perpendicular to the surface 2R, and a blue light source part 11B is placed opposite to the other surface 2B of the dichroic prism 2 parallel to the surface 2R. Here, the red light source section 11R, the green light source section 11G, and the blue light source section 11B correspond to the above-mentioned light source section 11, and introduce red, green, and blue light beams into the dichroic prism 2, respectively.

The video display device 1 further includes an integrator 12 placed parallel to the plane 2G, the first and second condenser lenses 13 and 14 , the light valve 15 , and the other plane of the dichroic prism 2 of the projector lens 4 .

In video display device 1 as shown in FIG. The red, green, and blue light beams input to the dichroic prism 2 are synthesized by the dichroic prism 2 in color. The color-synthesized light passes through the integrator 12 , the first and second condenser lenses 13 and 14 , and is irradiated on the light valve 15 . The light impinging on the light valve 15 is spatially adjusted by the light valve 15 . The spatially adjusted light passes through the light valve 15 and is projected on the screen through the projector lens 4 .

The video display device 1 here also has such a configuration as described above that since the light emitted from each light source portion 10 is condensed and introduced into the corresponding light valve 15, the number of light source portions 10 can be increased when necessary. to increase the amount of light. Furthermore, since the light from the light source portion 10 is condensed at a certain predetermined focal position of the optical axis of the entire illumination system, and the integrator 12 is placed on the focal position, the light can be uniformly irradiated on the light valve 15 , and the light emitted from the light source section 10 can be efficiently introduced into the light valve 15 .

The present invention can also be applied to video display devices including polarization switching.

In this way it is possible to obtain a video display device comprising polarization switching, for example, by at least one position between the light source part 11 and the integrator 12, between the first fly's eye lens 19 and the second fly's eye lens 20 At another position of , and at a further position between the integrator 12 and the light valve 15, such a polarization conversion unit 50 as shown in FIG. 14 is provided for the above-mentioned video display device.

Referring to FIG. 14, for example, a polarization conversion unit 50 may be formed by a polarization beam splitter 50a and a half-wave polarization plate 50b. The light introduced into the polarization conversion unit 50 first enters the polarization beam splitter 50a. Of the light introduced into the polarization beam splitter 50a, S-polarized light whose polarization direction is perpendicular to the incident plane is reflected by the reflection plane of the polarization beam splitter 50a, and is introduced into the half-wave polarizing plate 50b. The half-wave polarizing plate 50b rotates the polarization plane of light entering therein. On the other hand, of the light introduced into the polarization beam splitter 50a, the P-polarized light whose polarization direction is parallel to the plane of incidence passes through the polarization beam splitter 50a and goes straight ahead.

As described above, since the video display device 1 includes the polarization conversion unit 50 for splitting each light beam into two light beams by polarization conversion, it is obvious that the double number of light emitting diodes 16 is used. Therefore, as described above, where such polarization conversion is used, the entire area of the light emitting region of the light emitting diode 16 of the light source part 11 is preferably set to be smaller than (L _LV1 × θ _LV1 /NA _LED ) × (L _LV2 × 1/2 of θ _LV2 /NA _LED ).

In the video display device 1, since the entire area of the light emitting region of the light source part 11 can be reduced in half by polarization conversion, not only miniaturization of the device can be expected, but also equal luminance can be obtained with half the power. Thus, the device can be formed for reduced power consumption.

Further, in the above description, although the light valve 15 is assumed to be a light-transmitting type light valve, the present invention is not limited to this particular configuration, and a reflection-type light valve may also be used alternatively.

For example, as a light-transmitting type light valve, an STN (Super Twisted Nematic) liquid crystal display element, a ferroelectric liquid crystal display element, or a polymer dispersion type liquid crystal display element can be used. Alternatively, elements in which liquid crystals are driven in simple or active fonts can also be used.

At the same time, as a reflective light valve, for example, a reflective liquid crystal display element, in which TN (twisted nematic) mode liquid crystals, ferroelectric liquid crystals, polymer dispersion liquid crystals, etc., are made of glass substrates or The driving electrodes set on the silicon substrate or the driving active elements are driven. In addition, it is also possible to use a liquid crystal display element in which light irradiated through the photoconductive film applies a voltage to the liquid crystal. Alternatively, a reflective display element such as a grating light valve may be used, having a structure that changes its shape or state in response to an electric field applied thereto.

While preferred embodiments of the invention have been described using specific terms, such description is for illustration only, and it is to be understood that modifications and changes may be made without departing from the spirit and scope of the following claims .

Claims (8)

1. video display devices comprises:

The light source part that comprises a plurality of the Lights sections, each the Lights section comprises the light source that is formed by semiconductor light-emitting elements or white light, and be used for the coupling optical element that is converted to parallel light from the light of described light emitted, described light source part comprises collector lens, this collector lens can be to from described the Lights section, and the light that has passed each described coupling optical element carries out optically focused on the predetermined focal position of the optical axis of the lighting system of described video display devices, wherein, described the Lights section be set at described light source part the plane in case from the light of described the Lights section by the described predetermined focal position of optically focused at described collector lens;

Be arranged on the integrator on the predetermined focal position of described light source part, be used for light intensity distributions in the plane of the light of described light source part emission is carried out homogenising; And

Rectangular light valve, light intensity distributions is thereon illuminated by the light of described integrator homogenising in its plane;

Wherein, the focal length of described collector lens represents with L, and, represent with H to the ultimate range of the optical axis of each described the Lights section from the described lighting system optical axis of described video display devices, described light source part is designed like this, so that satisfy the relation that following formula provides:

|H/L|＜0.27。

2. according to the video display devices of claim 1, wherein,, want the maximal value θ of the described light valve on the side surface direction secondarily with angle with respect to the optical axis of the illuminator of described video display devices, the light that on described light valve, shines ₁Expression, the maximal value of the described light valve on its main side surface direction is by θ ₂Expression, the length of the described light valve on the secondary side direction is by L ₁Expression, the length of the described light valve on main side surface direction is by L ₂Expression, and the effective numerical aperture of described collector lens represented that by NAc described light source part is designed like this, so that the area S of the luminous zone of described the Lights section satisfies following formula:

S≤(L ₁×θ ₁/NA _c)×(L ₂×θ ₂/NA _c)。

3. according to the video display devices of claim 1, wherein, described light source is formed by light emitting diode or laser diode.

4. according to the video display devices of claim 1, wherein, described light source part comprises catoptron, is used for the light from a direction reflection from light emitted.

5. according to the video display devices of claim 1, wherein, the luminous zone that is formed by described the Lights section of described light source part has the flat shape identical with described light valve.

6. according to the video display devices of claim 1, further comprise the polarization conversion element, it is set on another position and a position in another position between described integrator and the described light valve of inside of the position between described light source part and the described integrator, described integrator at least.

7. video display devices comprises:

The light source part that comprises a plurality of the Lights sections, each the Lights section comprises the light source that is formed by semiconductor light-emitting elements or white light, and be used for the coupling optical element that is converted to parallel light from the light of described light emitted, described light source part can be to from described the Lights section, and the light that has passed coupling optical element carries out optically focused on the predetermined focal position of the optical axis of the lighting system of described video display devices, wherein, it is on the hemisphere at center that described the Lights section is set at described focal position, so that can be by optically focused on the focal position from the light of described the Lights section;

Be placed on the integrator on the focal position of described light source part, be used for light intensity distributions in the plane of the light of described light source part emission is carried out homogenising; And

Rectangular light valve, light intensity distributions is thereon illuminated by the light of described integrator homogenising in its plane;

Wherein, described focal length represents with L, and, with H represent to the ultimate range of the optical axis of each described the Lights section that from the described lighting system optical axis of described video display devices described light source part is designed like this, so that satisfy the relation that following formula provides:

|H/L|＜0.27。

8. according to the video display devices of claim 7, wherein,, want the maximal value θ of the described light valve on the side surface direction secondarily with angle with respect to the optical axis of the lighting system of described video display devices, the light that on described light valve, shines ₁Expression, the maximal value of the described light valve on its main side surface direction is by θ ₂Expression, the length of the described light valve on the secondary side direction is by L ₁Expression, the length of the described light valve on main side surface direction is by L ₂Expression, distance from described the Lights section to described focal position is represented with L, and, represent with H to the ultimate range of the optical axis of each described the Lights section from the optical axis of described lighting system, described light source part is designed like this, so that the area S of the luminous zone of described the Lights section satisfies following formula:

S≤(L ₁×θ ₁×L/H)×(L ₂×θ ₂×L/H)。

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